For some time now i have been messing around with transformers,using magnetic core's.The one described below is the best results so far.The schematic preaty much says it all,in reguards to this setup,except the transformer configuration itself.In reguards to the scope shot's,the yellow trace is across the input resistor,and the blue trace is across the output resistor. The transformer is a 1:1 bifilar type,and has a magnetic core,but not aranged the way you may think.
Although this is more than likely wrong,it seems we have .0158 watts being disipated across the input resistor,and .0363 watts being disipated on the output resistor. You will also clearly see the phase shift between the primary and secondary-maybe due to the high frequency,or the magnetic core?
MH and TK-i would like your opinion on this one.
I forgot to mention that the frequency needs to be fairly close to right,or we dont get good result's. In the below scope shot,i have thrown the frequency out,and it now clearly is using more power than it is outputing.
In the below scope shot,i have replaced the 3 ohm resistors with .1 ohm 5 watt CSR's.Everything else remains the same. The results seem to be better with the lower resistance CSR's.
Im not sure what the noise is you see on the wave form to the right of the scope shot.It seems to flow through the wave's from left to right on the scope-kinda looks like small explosions in the wave forms.
I also had to raise the frequency with the lower resistance,to gain maximum amplitude on the output wave.
Tinman:
It's worth it to take a fresh look at this and I will give you a few pointers.
Comparing the power dissipated across the "input resistor" to the "output resistor" is unusual and I fail to see how useful that comparison is. Look at your schematic; the input power to the circuit is supplied by the signal generator so you should be measuring that. That input power goes to two places, R1, the "input resistor" and the transformer primary. So the "input resistor" is just one load among other loads that dissipates power supplied by the signal generator. The primary of the transformer looks like another load to the signal generator. That primary couples power to the secondary, and that power gets split between R2 and R3. In addition, each winding of the transformer has a 0.5 ohm equivalent resistance and those are also dissipating power.
With the understanding of where the power is flowing, what is a meaningful comparison? Perhaps the input power from the signal generator compared to the power dissipated in R2 and R3? That's for you to decide but I don't see any merit in your original approach of comparing the power dissipated across the "input resistor" to the "output resistor." I see the input power from the signal generator being dissipated into five resistive loads (including the winding resistances.)
You are working with sine waves so you are supposed to measure power across resistors based on the RMS AC voltage. By the same token, you want to look at the phase angle between signal generator voltage and the signal generator current to measure the input power to the circuit. You also might be interested in seeing how the phase angle (and therefore input power) varies with frequency.
MileHigh
Hi MH
Well im using the .1 ohm CSR's now-is this not how a DMM work's?. From the voltage across resistance,can we not calculate power?
Below is the mod schematic,and scope shot with RMS value,s.
Sounds like an interesting setup however I can see what MH is saying. Right now it seems you are measuring the power dissipation across a resistor on each side of the transformer but that does not mean it's the total power used in the circuit. I believe you would see more power measuring across the input from the sig gen as well as more power at the output across the transformer. If that output is still higher than input I believe you have something to get excited about. ;) But that's just my thoughts -- I think both you and MH are way ahead of me on theory.
Tinman:
From the voltage across a resistance you can measure the power dissipated in the resistance itself. I can't be sure, but you seem to be indicating that you can measure the input power to the circuit like that, but you can't.
Note by measuring the voltage across a resistance you are also measuring the current through the resistance. In looking at your first circuit you have two current loops and a bunch of known resistances in those loops. So you have enough information available to measure the power dissipated in each individual resistive component in the circuit, and thus the total resistive power dissipation of the entire circuit.
The next step would be to measure the input power to the circuit as supplied by the signal generator and compare that to the total power dissipated by the circuit.
MileHigh
P.S.: This is a bit more advanced: Let's say you now know how much power is being dissipated by the entire circuit. You also know how much current is flowing in the signal generator current loop. Then you measure the signal generator voltage.
In theory that gives you enough information to determine the phase angle between the voltage and the current supplied by the signal generator, no scope required. So if you make good measurements, you should be able to hook up your scope with an expectation of what the phase angle should be before you even see it.
Just for fun let's try going one step further.
I am going to make some assumptions about two other parameters. I don't know the wire lengths in the setup. All that I know is the signal generator frequency is close to one megahertz so I will take a guess that there are some observable inductance effects. That would show up as a lagging phase angle in the signal generator current compared to the signal generator voltage. I am also going to assume that there are measurable losses in the core. Of course there are losses in the core, but are they measurable or not is the question.
So the goal is to measure the losses in the core by inference from other measurements. You have an accurate measurement of the total resistive power dissipation of the circuit. You try to measure the signal generator voltage and current and phase angle as accurately and carefully as possible. Here is where you play with the horizontal and vertical stretching on your scope display to line up a single or half sine wave with the display graticule. That makes it easy to make precise phase angle measurements.
Your real power measurement with your scope is Vrms x Irms x Cos theta. Compare that with the total resistive power dissipation of the circuit. If the scope-measured real power is greater than the total resistive power then you can infer that the "extra" power measured by the scope method is due to the heat power losses in the core.
Then if you run your circuit for say ten minutes and compare the before/after core temperatures you might get basic empirical confirmation that the core is indeed heating up. If you just can't stop taking extra steps, you could measure the rate of core temperature increase and knowing the mass and specific heat of the core material, measure the heat power in the core that way. Not too difficult to make slight physical changes to the bifilar coil so the core itself is in a thermal tomb. The coil would not be affected electrically. Then compare that core heat measurement with your derived core heat power from the scope measurement. That might be something that's right up TK's alley. It's like a vivisection!!!
See now that would be fun for me! The funny thing is I never made these kinds of measurements in real life. lol
MileHigh
Last gasp....
How can you get the most accurate total thermal power dissipation measurement?
You know that you have quite accurate current measurements for each loop, which is a good start. So with your multimeter, you measure the electrical resistance for the entire loop, i.e.; all the components in series. So you make only one resistance measurement with your multimeter for each loop, which is much more accurate than adding individual measured resistances together. Note this also factors in the total wire resistance in each loop.
This helps in the quest to measure the power dissipation in the core by inference.
Quote from: MileHigh on August 31, 2013, 06:27:46 PM
Last gasp....
How can you get the most accurate total thermal power dissipation measurement?
You know that you have quite accurate current measurements for each loop, which is a good start. So with your multimeter, you measure the electrical resistance for the entire loop, i.e.; all the components in series. So you make only one resistance measurement with your multimeter for each loop, which is much more accurate than adding individual measured resistances together. Note this also factors in the total wire resistance in each loop.
This helps in the quest to measure the power dissipation in the core by inference.
Mmm-a couple of problems here.
The resistance of L1 will go up with frequency,along with L2,due to the skin effect.
Second problem-my DMM's are usless at these frequencies,as they read 0 on amp's ,and voltage is all over the place-both AC and DC setting.
So i will have to use the scope to measure across the resistor,then also across the coil for voltage.
As the power level's are very low here,the core dose not change in temp that i can detect with my IR temp gun,not even .2*f-after 30 minutes running.
Tinman:
Note the impedance of the inductors will go up with frequency but I am only interested in the DC resistance measurements for the two coils that form the bifilar. Also, the bifilar coil is a 1:1 transformer in this circuit and that means it actually looks like a resistive load because the secondary of the transformer is connected to a resistive load. So it's probably fair to say that any possible high frequency inductance effects would be only due to the parasitic inductance associated with the lengths of the wires in the overall setup and the geometry and not due to the bifilar coil itself.
So it would be something like this: (first circuit)
1. Measure the values of R1 and R2.
2. Measure the DC resistance of each complete loop.
3. Connect the signal generator and run the setup.
4. Measure the RMS voltages across R1 and R2 to derive the RMS currents in each loop.
5. Crunch the numbers and get the power dissipated in each loop to find the total power dissipated by the circuit.
I didn't think about the skin effect and it may also come into play. It would lower the RMS currents, and you are measuring the RMS currents so you are at least accounting for the skin effect in the current measurement. However, the effective DC resistance of the circuit would also increase because of the skin effect and you can't directly account for that. Let's not go there because it will get too complicated and I may already be talking too much.
If you are interested in the measurements you could try to do the whole thing at a much lower frequency, like 500 Hz or 1 KHz. Chances are the possible inductive effects of the wiring and any possible skin effects will become negligible. In other words, bite off only so much at a time.
A similar issue applies for measuring the RMS voltages across the two resistors when the frequency is 690 kHz. I don't know if your multimeter will make that measurement properly. If you are not sure yourself here you have the advantage of being able to check the multimeter measurement against the scope measurement. You absolutely must have the reference and signal contacts for both probes on exactly the same contact points at the same time. Again, you can also compare the two measurements at 500 or 1 kHz with the expectation that they will be very close. When you compare the two measurements at 690 kHz, there is a possibility that the multimeter would show a lower RMS voltage than the scope because of a high frequency roll-off effect.
You may laugh but I would not use the RMS voltage display on your scope until I knew your scope and knew that I could trust it. I would divide the peak voltage of the AC waveform as read off of the display with my eyeballs by the square root of two to get the RMS voltage. If your built-in scope RMS measurement was consistently in agreement with my "read the scope display by yourself and crunch" method then I would come to trust it.
If you do this, and then after the fact measure the DC resistance of all of the resistive elements in the circuit then you will be able to crunch the power dissipated in every component in the circuit. That includes the individual windings of the bifilar coil.
MileHigh
Grr. You are operating at two thirds of a megahertz. The DC resistance alone of the coils is almost irrelevant, would only become relevant if you were doing a DC control heating run. For the purposes of input and output power measurements, and for the scope shots to make any sense you need to know the total AC impedance of the coil and of the resistors. And even the interconnecting wiring. So you really need the inductance values of the coils and the wiring. You can calculate the inductance of the wiring from the dimensions, and you should be able to measure the inductance of the coils using any of a number of methods I and others have detailed, even without an inductance meter. Once you know the total AC impedance of the system then the power measurements will start to be interpretable. You may find that the left side and right side impedances are more different than you think, and this will of course affect your interpretation of the scope's voltage readings.
I have no problem with using a 0.1 ohm inline resistor for a current viewing resistor, and you should be able to monitor the voltage across the FG leads directly, so on the input you have Two traces that you can take a snapshot of, then laboriously hand-multiply some points together to get the instantaneous power function for the input. Then you can swap the probes over to the output 0.1 ohm resistor, and across the output transformer total load, and then do the same manual calculation for the output side. Using this method you don't need to worry about the impedances or phase relationships at all (yet...), all you need to do is compare areas of the resulting input and output instantaneous power functions.
On an analog scope or a 2-ch DSO that can't do math, it's a tedious process, but if you do it patiently you can arrive at answers that are within 5 percent of those you get using real 4ch topline DSOs with full on internal math. I know because I've tried it... several times.
It might take you four hours to get a good power function for the input, and another four to get the same for the output. Is overunity really worth all that work?
;)
TK:
Are you sure you are not complicating things even more than me? lol My comments assume that Tinman is using a wonderful simple sine wave output from his signal generator. That's what we see in the scope shots. So all that you need is to work with sine wave excitation is RMS values and phase angles. There is no need to become a human DSO with built-in math!
MileHigh
Well i now am starting to see why it's hard to learn how to measure things correctly.
Quote MH: but I am only interested in the DC resistance measurements for the two coils that form the bifilar.
Quote TK: Grr. You are operating at two thirds of a megahertz. The DC resistance alone of the coils is almost irrelevant, would only become relevant if you were doing a DC control heating run.
So two great minds telling me two different thing's? ???
Anyway,below is a scope shot of the input current and voltage .
CH1 is across the coil,and CH2 is across the .1 ohm resistor. Both grounds of the scope on the common conection ofcourse. Now with some more adjusting,i can get the current 180* out of phase with the voltage. Also i found it interesting that by adjusting the offset on the SG,only the current trace changed-the voltage trace remaind as is. From a 2 dimentional point of view,i can raise or lower the current trace through the voltage trace.
Tinman:
Myself and TK are not necessarily in disagreement. We might have different reasons for what we are saying. I am interested in the resistance of the coils, it's for the power dissipation measurements.
I suspect that TK made a reflex call but he can clarify that if he wants to. He is making reference to the AC impedance of a coil of the bifilar at 690 kHz being much higher than the DC resistance of the coil. I also stated that it's not a coil, it's a transformer, and on the far side of the transformer (the secondary) there is a resistive load. So the primary "coil" of the bifilar transformer will have the characteristics of a resistor and the AC impedance at "conventional" high frequencies will not come into play.
Big disclaimer: I note that I am saying this sight unseen and I am assuming that your bifilar coil/transformer is a typical "fist sized" coil. I don't really know how your bifilar coil will respond when acting as a transformer at 690 kHz. I would have to sweep it on the bench to find out. TK and others have much better "feel" for these things and can make better preliminary estimates than me because they have the hands-on experience that I don't have. You have to understand the context - people that work as engineers and technicians on the bench don't normally do these kinds of tests at all. I never had any reason to do a bandwidth sweep of a hand-made bifilar transformer to see how it would work at 700 kHz.
MileHigh
I see you have the required tools to go with any measurements you like. Wonderful!
May I propose a big shift forward ? Gentlemen,that's all I can do because I have no tools or Your huge experience and knowledge in electronics.
If you are willing to test it anyway plesae provide us with explanation and video. Please correct me if I'm wrong.
This big shift starts with parallel resonant LC circuit. If you take a incandescent bulb and measure the power required to light it to certain intensity using DC current , you can do the same using less if you place this bulb in parallel resonant tank circuit powered by proper impulses. Correct ?
Now please tell me and give a proof we can do the same placing this bulb on the secondary of transformer (for example 1:1 transformer ratio) with the primary having a capacitor to still forming parallel tank circuit, powered like before from a signal generator impulses (probably that require a ferrite core transforemr with bifilar coils because at higher frequency it will be easier to adjust)
Possible ? Can you measure light intensity and compare to the input power ?
@ Forest
My setup isnt a tank circuit-no cap's. And what you are asking(as far as i understand) has been done befor,and isnt hard to do.I have done it with pulse motors many time's.
@ MH
The L1 L2 resistance value is on both schematic's posted,along with R1 R2 and R3.
Or am i misunderstanding what you need?.
Now the transformer configuration is this. I have use heavy gauge speaker wire,and completely raped a large speaker magnet with it-this is the transformer.The speaker magnet is 5 inches in diameter,and made from ferrite ofcourse.
Hi Tinman.
My understanding is that all coils have some capacitance. Hence, all coils have a natural resonant frequency.
As your 2 coils are wound together, there is capacitance between them too. So even without having capacitor components, you'll still have a tank-circuit.
Regards
Tim
Hi Tim
Yes there would be capacitance,but extreemly low in value with the small amount of turns,and copper being used. I believe it to be more of a result from the interaction between the electrical field,and the magnetic field. Also keeping in mind,we are using a toroid core aswell,wich forms a loop. If we look at how this is set up,when we have an alternating current through coils of wire that is wound at right angles to the magnetic field of the core,we would be creating a magnetic field wave around that magnetic core aswell.
What i find interesting is that not only can we shift the phase(voltage/current) out by 180*,i can also offset the current to all be below or above the zero volt line,without effecting the voltage wave form.
Now it all looks good on a 2 dimentional scope screen,but what would this look like in 3 dimentional?.
It'd be interesting to measure the capacitance between the coils. I bet it's significant. There must be both inductive and capacitive coupling between the 2 coils. Perhaps that explains the phase shift?
The scope traces look to me like typical 'reactive' volts from running a coil at it's natural resonance point. I.e. the impedance drops, more amps flow on the input at less voltage, and higher volts appear on the output. I could be wrong...
I was watching your 'Rotary Transformer' vids yesterday. I'm fascinated. I can't figure out how it works. Gonna have to make one... Did you ever hook it up to a generator? :)
Quote from: tim123 on September 01, 2013, 09:07:51 AM
I was watching your 'Rotary Transformer' vids yesterday. I'm fascinated. I can't figure out how it works. Gonna have to make one... Did you ever hook it up to a generator? :)
Ah ,some one is starting to put all the pieces together. How exactly do you circumvent lenz force? or use it to your advantage?.
I will be interested to see if you can work that one out (the rotary transformer).
There are many on my forum who are still trying to work that one out.
I have just aquired another of those exact motor's,so now one will be the development block,(will be choped,bent and shaped),and the other will be the final product once we know what give's the best result's.
Hi Tinman. I've figured out how it works (Rotary Transformer). It is genius mate.
Is this open source? Given the principle of operation - it's possible to improve on... The universal-motor hack isn't bad, but it's far from an optimal configuration... Really need more stator poles, not so big, eh...
I think you've totally cracked OU with the RT mate. Awesome. :)
Do we need a new thread here, to cover the RT?
Tim
Quote from: MileHigh on September 01, 2013, 12:53:15 AM
TK:
Are you sure you are not complicating things even more than me? lol My comments assume that Tinman is using a wonderful simple sine wave output from his signal generator. That's what we see in the scope shots. So all that you need is to work with sine wave excitation is RMS values and phase angles. There is no need to become a human DSO with built-in math!
MileHigh
Using the method I showed the only math you need is addition, multiplication and division. You don't need to measure phase angles or calculate trig functions, and the method I show works with any waveforms or phase shifts, because it results in a sample-by-sample instantaneous power value, which you can then integrate later to find average power dissipation or energy flow.
It's tedious to do it by hand, sure... but it works and it is as accurate as you are meticulous. You can certainly work with phase angles and RMS values for sine waves... if you are sure your waves are sinusoidal, you can measure the phase angle correctly and you are comfortable with the trig. But this only works with sinusoidal waves.
You should be able to see from tinman's traces that the phase relationship varies. But there isn't an easy way to measure the phase differences using his scope, I don't think. Maybe there is, I'll have to check the Atten manual. It might be neat to put the scope into x-y mode and see what kind of shapes you get.
Doing a manual multiplication and integration from an analog or non-math digital scope is tedious, not complicated. There is a difference. Digital photography makes it a lot easier. Can you imagine taking a film photo, with your special Polaroid camera, of the scope screen then cutting the traces out of the photograph and weighing the shapes on an analytical balance? Or transferring to graph paper and counting little boxes of areas? That is what people did before digital storage scopes, and they did a lot of it.
Quote from: tinman on September 01, 2013, 01:00:53 AM
Well i now am starting to see why it's hard to learn how to measure things correctly.
Quote MH: but I am only interested in the DC resistance measurements for the two coils that form the bifilar.
Quote TK: Grr. You are operating at two thirds of a megahertz. The DC resistance alone of the coils is almost irrelevant, would only become relevant if you were doing a DC control heating run.
So two great minds telling me two different thing's? ???
(snip)
Heh... not really. I think that the inductances are going to contribute more to the total AC impedance than the resistance will. MH perhaps thinks the opposite. But it is the total AC impedance that must be used in "ohm's law" kinds of calculations, not just the DC resistance component of the total impedance.
OK, I am lost here. A long time ago I had the idea of using a neo ring for a JT core and was told that you can't use a magnet for a core because the field never collapses completely and therefore you can't get anything out of it. So how is Tinman seeing anything out of this set-up?
As I said, I am lost and just simply do not understand this at all. (Nothing new for me)
Bill
Bill:
Of course we see many clips and free energy propositions with magnets being used as cores for coils in various setups. It's actually one of those things that doesn't make sense but still has a life of its own. The logic is simple: We know coils need AC flux to respond and we know magnets produce unchanging "DC" flux. Therefore the coil will be unaffected by the magnetic property of the core.
It's safe to assume that using a magnet as a core will be inferior to using a regular ferromagnetic core material. Have you ever seen any clips where someone does an A-B comparison test between a regular core and a magnet as a core in some kind of setup? The other thing worth mentioning is that if you use a magnet as a core you risk demagnetizing it.
MileHigh
MH:
Thank you for the response. No, I have never seen anyone do an A-B comparison of magnetic vs ferromagnetic cores, all else being equal. It seems to me this might be a valuable experiment for someone to do.
I am thinking that using a magnetic core would make the device operate at a very high frequency. The reason I say this is because, if you build a JT and it squeals, you can raise the frequency above human hearing by placing a neo on the core, then, you can't hear it. This I have done many times but, I had no idea that the entire core could be of a magnetic material.
Possibly, one could take a speaker magnet, like Tinman, which is ferrite, and heat it above the currie temp. for that type of magnet, and wind up with a nice large ferrite core. (Now non-magnetic) This is something I may look into doing as the sources for the large ferrite cores appear to be long gone, unless you want to pay a lot of money.
Thanks again,
Bill
Quote from: Pirate88179 on September 01, 2013, 03:26:14 PM
OK, I am lost here. A long time ago I had the idea of using a neo ring for a JT core and was told that you can't use a magnet for a core because the field never collapses completely and therefore you can't get anything out of it. So how is Tinman seeing anything out of this set-up?
As I said, I am lost and just simply do not understand this at all. (Nothing new for me)
Bill
The magnet will work as a core, just a bit different.
We have seen others devices with magnets in the cores. In industry they are called Hicore and Hiformer, hiformer for transformer with magnet in core to magnetically bias the core. Hitachi Magnetics Corporation. ;)
In a pulse mode situation, The greater current handling capability is clearly evident, about twice the volt-ampere capability before saturation as the same core without the bias magnet. Of course the pulse polarity will have to be according to the set magnet polarity, as the opposite polarity will reduce the current handling.
In your situation using a ring magnet, the magnetic field is polarized on the flat sides of the ring, not through the rings circumference like a Hiformer would be, but the ring you have will have some affect on what transpires in the transformer vs a core of like size. That would have to be looked at to see what those differences are. ;) And being the ring magnet is not polarized against nor with the coils magnetic polarity, more like perpendicular, input electrical polarity makes no difference from what I gather. ;)
Demagnetization of the magnets in these devices used to be an issue till the advent of rare earth magnets. ;)
Mags
Bill:
My suspicion is that the neo magnet reduces the energy storage capacity of your JT core. In other words, it lowers the effective inductance of the core + coil arrangement. That should tend to make the JT oscillator run at a higher frequency. Some bench tests could be done to see if an approaching neo will do that to the core.
MileHigh
Quote from: tim123 on September 01, 2013, 02:23:11 PM
Hi Tinman. I've figured out how it works (Rotary Transformer). It is genius mate.
Is this open source? Given the principle of operation - it's possible to improve on... The universal-motor hack isn't bad, but it's far from an optimal configuration... Really need more stator poles, not so big, eh...
I think you've totally cracked OU with the RT mate. Awesome. :)
Do we need a new thread here, to cover the RT?
Tim
Hi Tim
The universal motor was just handy at the time,and yes-it could be made much more efficient, but we use what we have handy at the time.You could have more pole's on the stator,but no more than half of that of the rotor.
Feel free to start a thread on it if you like,and share how you believe it work's,im interested to see how close you are.
New thread started on the Rotary Transformer... :)
http://www.overunity.com/13777/tinmans-rotary-transformer/
Quote from: MileHigh on September 01, 2013, 06:02:10 PM
Bill:
My suspicion is that the neo magnet reduces the energy storage capacity of your JT core. In other words, it lowers the effective inductance of the core + coil arrangement. That should tend to make the JT oscillator run at a higher frequency. Some bench tests could be done to see if an approaching neo will do that to the core.
MileHigh
MH is right. Bringing a magnet close to the core will bias (polarize) the core causing its permeability to decrease. Hence the inductance of the coil decreases.